It's all about control; nothing more, nothing less. He can be a nice guy, who a woman thinks she knows so well. Nn my case, I knew him for many years, albeit in a different context. Yet he may spend his alone time being angry and frustrated. He then has no one else to take out those feelings on but his partner.
Eventually, her friends see enough signs that she has changed, is isolated from them, and doesn't seem happy. Hopefully, they try to intervene and offer their support and help to get her out of what is obvious to everyone else but her is an abusive relationship. Friends aren't deaf or blind, they will support you in getting out. Real friends will not enable you if you choose not to leave an abusive relationship.
There's no joy in knowing others are dealing with the same types of issues I did, whether it's explaining to your kids why your ex-partner (who they loved) is no longer in their lives, or why his kids (their best friends) aren't either.... or about why Mom seems sad a lot. Why mom's boyfriend is doing erratic things and acting weird at your house. A child's home should feel safe and be free from relationship drama of their parent and her partner.
The lasting impact of trauma gets easier over time, but it's hard work. All I know is tonight, because of the same person who hurt me, there is another woman suffering, maybe in the same way, maybe along with her kids. Maybe she doesn't even realize it. When you love someone, you don't want to believe they are capable of hurting you, cutting you off from your life as you knew it, or telling you to say or do things which paint someone in their past in a negative light. It's a sort of attempt to use you as a beacon of vengeance.
I didn't want to believe this person would do this and, years later, it still stings. One of the reasons it hurts so damn much is that there is not closure in that kind of relationship- you never know what happened or why, if he ever loved you at all, or if he was just using you to hurt someone else.
My thoughts and prayers go out to women who have left, or who have been left by, their partners, the final act of a relationship which had become violent and/or controlling, something that didn't feel safe or joyful any longer. Break-ups in general suck. What makes leaving an abuser feel exceptionally painful is that it feels like it is all your fault. After all, it takes two adults to stay in any relationship and there are reasons people stay which make sense in the here and now, but not in the rest of reality.
Lots of healing can be accomplished by letting in good friends, family who love you unconditionally, and by relying on whatever faith you practice. After all, it takes a village to raise a child. We single moms are the leaders of our families, and we need to accept the care and support of people who love both us and our kids. I shed a tear today (ok, more than a few) for the strong women who chose to leave. And maybe, somewhat selfishly, a single tear has been shed from my eyes because I no longer feel so damn alone in this experience.
There's nothing more I want to say. I saw him, with my own two eyes, do it again to someone else. It sucks to be right.
To learn more about domestic violence, a good resource is the book "Why does he do that?" by Lundy Bancroft.